Numerous iPhone users discovered they were logged out from the Facebook app on Friday evening, a problem put down to a "configuration change" by the social network.Posts from iPhone users started to appear on social media and Reddit on Friday evening, claiming they were logged out from the Facebook app after their session expired. The sign-in prompt appeared on their devices, despite not logging themselves out from the account on their smartphone.Users who had set up two-factor authentication on their accounts were also having trouble logging back in, as there were long delays in the sending out of text messages for those who elected for SMS-based codes.Read more